Optimization of autoclave and microwave assisted alkaline hydrolysis for release of ferulic acid from biomass

Abstract

© 2017, Chiang Mai University. All rights reserved. Ferulic acid is phenolic acid which exists in plant cell walls and has many physiological properties including antioxidant, antimicrobial, anticancer and anti-inflammatory activities. In this study, ferulic acid was obtained from lignocellulosic biomass by autoclave assisted alkaline hydrolysis (AAA) and the process was compared with microwave assisted alkaline hydrolysis (MAA). The results from the phenolic analysis of lignocellulosic biomass by HPLC showed that when lignocellulosic biomass was hydrolyzed by 0.5 M NaOH for 15 min in the autoclave, the corn husks and corn cobs released high amounts of ferulic acid. The effects of applying different concentrations of NaOH (0.25, 0.5, 1.0, 1.5 and 2.5 M) and hydrolysis time (5, 15, 30, 45, 60, 75 and 90 min) in order to release ferulic acid using an autoclave and a microwave were investigated. The results showed that the utilization of 0.5M NaOH for 60 min was the optimal hydrolysis condition for the release of ferulic acid from corn husks (20.48±0.13 mg/gsample) and corn cobs (17.09±0.01 mg/gsample) by AAA. However, hydrolysis by 1.5 M NaOH for15 min and 2.5 M NaOH for 15 min in a microwave could release high amounts of ferulic acid from corn husks (31.14±1.10 mg/gsample) and corn cobs (19.51±0.01 mg/gsample), respectively.